JavaScript Basics Module #16

Question 1

What kind of error do you get if you try to reassign a new value to a const variable?

Answer 1

TypeError

Question 2

Which 2 use cases can a const variable point to in which the content changes?

Answer 2

Object or Array

Question 3

Which kind of variable should be used most often and why?

Answer 3

const because the less power our code has the better. This way, less bugs are introduced into our program.

Question 4

What are the 4 primitive types?

Answer 4

Numbers, strings, booleans, symbols. There are also 2 special types, “null” and “undefined”.

Question 5

What is an object type?

Answer 5

Any value that is not a primitive: (string, number, boolean or property).

Question 6

What’s an expression?

Answer 6

A single unit of JS code that the JavaScript engine can evaluate.

Question 7

Logical Expressions have 3 types, what are they?

Answer 7

&& (and) | | (or) !a (not)

Question 8

What happens in JS when you divide a number by 0?

Answer 8

No error is returned, instead the value of Infinity or (-Infinity) is returned.

Question 9

What is returned by this expression 1 % 0?

Answer 9

NaN (Not a Number)

Question 10

What is returned by this expression -1 % 0?

Answer 10

NaN (Not a Number) Any time you use the remainder operator on a zero, it returns NaN.

Question 11

How is the exponentiation operator expressed?

Answer 11

**

Question 12

In JavaScript what is the order of operations for operators?

Answer 12

Multiplication, Division, Remainder, addition and subtraction. Anything inside of parenthesis are evaluated first.

Question 13

What are the equality operators?

Answer 13

===Equality strict, !== Inequality strict (also == eqaulity and != inequality operator) *Strongly suggested to only use the strict operators ( less errors and less problems that are difficult to troubleshoot/diagnose)

Question 14

How do you set up an if statement?

Answer 14

if (condition true){
// do something
}

Question 15

How do you set up an if /else statement?

Answer 15

if (condition true){
// do something
} else {
//do something else
}

Question 16

How do you set up an “else if” statement inside of an “if” statement? Don’t forget to include the fallback.

Answer 16

if ( a === true ) {
//do something
} else if ( b === true ) {
//do something else
} else {
// fallback
}